Barrastus is a ruined city in the Black Hills badlands between the Lahrus Plains and the Stone Flow, on the core-fragment of the Plane of Varys. In its prime Barrastus was a powerful city-state, closely allied to the Golden Land, and was influencial in the great wars of the Seventh Age.
Much of the city's power and influence could be attributed to the Barrastus Archive, which contained the bulk of lore salvaged from the Rusanti heartlands as they were gradually engulfed by the Stone Flow near the start of the Seventh Age. Barrastus actively sought to expand the archive over the following centuries, and served as a beacon of knowledge and cooperation in an otherwise dark age - as well as a military power of some note.
Barrastus' golden age was cut short near the end of the age when the Devouring Mist settled across the eastern part of the Lahrus Plains and reduced everything there, including Barrastus and its outlying settlements, to seething, toxic muck. The few ruins that somehow survived this dreadful fate barely hint at the city's great history, making the full extent of the loss hard to imagine.